Automatic stoker



2 Sheets-Sheet 2 R. D. CRAWFORD AUTOMATIC STOKER Filed Jan. 18, 1928 April 16, 1929.

INVEN TOR, 9. 4

I ATTORNEY Patented Apr. 16, 1929,

UNITED STATES PATENT OFFICE.

RALPH D. CRAWFORD, MAMARONECK, NEW'YOBK.

AUTOMATIC STOEE'R.

Application filed January 18, 1928. Serial No. 247,568.

nels which convey the coal, thus increasing the neatness of operatio'nof the stoker; also, to

, accomplish these results .by the same means which create the forced draft utilized withthe stoker, thus simplifying the mechanism and avoiding duplication of operative means.

In the accompanying dr'awings, in which I have shown iny improvements as applied to an under-feed stoker adapted for use in the smaller classes of furnaces, such as are used for heating residences and the like, Fig. 1 is an elevation of an apparatus embodying my invention partially broken away to show in terior construction; Fig. 2 is another elevaably carried. around the inner lsides of" the tion taken as looking to the right on Fig. '1, the fire pot being omitted; Fig. 3 is a plan view; and Fig. 4 is a sectional VleW, taken on the line of Fig. 2, looking down,.part of the feed-chute and air duct being broken away to show the interior construction.

A hopper 1 is provided with a sloping bottom 2, leading to anoutle 3, connecting with a tubular duct 4, provided with a feed-worm 5, journalled in bearings as t} at the fire-pot end and 7 at the opposite'end. An electric motor &.is' provided .yvith a shaft 9, carrying a worm l1, meshing'with a worm gear 12, which through itsshaft 13 and arm 14, connecting'rod 15, aim 16 and pawl 17, engaging with ratchetwheel 18 o'n the end of the worm shaft 19, rotatesi the worm step by step to force coal, for instance such as the grades called buckwheat, supplied throu' hojthe outlet '3, to the fire pot 21, in an un erfeed manner.

A conventional blower fan element 23 is driven by the shaft of the motprS, and its discharge is connected, by a pipe 24, With! pipe 10 jacketing'the duct 4, sot forward by the fan is forced 'along' the pipe 10 to the fire pot, where art of the air passes the fire, through t e holes 22, 22, and

at the air driven part rises around the fire pot to assist in the process of burning the gases evolved in the fire pot.

The fire pot 21 may be placed within the fire box of afurnace, or in any place suitable to 1 utilize the evolved heat, as will be readily understood by those familiar with tlie art.

These portions of the ap aratus are old; and they are shown and exp ained simply to make clear the application ofmy-improvej ments. 1

L The fan element 23 isprovided-with a centrally disposed inlet opening within-a neck 25 shown in broken line in- Figs. 2 3 and 4. Over this neck I place a sleeve 26, preferablyprovided with a rose damper 27, and oonnected with a pipe 28 extending up toand-com" nected throughthe overhangin 293 f a hood'30 partially covering 6410 16 hopper 1 at one end, This hood- 3 above and at its sides 31; 32, but: over the hopper is'open, although that, [)0 of the bottom extending beyond "theside' of the hopper is closed. -4

A downwardly'deflected flange 33is prefer hopper 1, not 'covered by the hood, its'ends being continued under the hood. The width and an le of this flange may be varied, as

circums nces may indicate." But it should 7 not be sufliciently wide to materially interfere,

with shoveling coal into the hopper 1 from within the hood 30 and forced-through the air pipe '10 to the fire. pot. Then-if'coal 1s shoveled into the' hopper .1, i the suction of magmas will draw :the'dust incidentally 'de; velop'ed in the. hopper along under the flange 33 andgenerally-under andtheh upward out of the hood 30 and forceititowards the point of combustion. The draft produced by the fab will besu'fi icient to quite efiectuall' control the coal dustordinarily evolvedm filli'ng'the hopper,.and toeliminatethediffusion of such dust outsidebf thehopfier and stokdirectly to the fan although if 'thefairicon a s With the fan element 23in operation, and 4 the-rose damper 27 closed, air.will' be drawn tinues to be drawn from the pipe 28, any incidental dust caused by the shifting of the coal in the hopper 1 in the process of feeding will be sucked up and prevented from spreading 5 outside of the apparatus.

' By this arrangement I am able practically to eliminate annoyance from dust diffused "from the hopper during the process of supplying it with coal; and to do this by utilizing the forced draft mechanism Without the aid of other power units or increased expenditure of power.

I desire it to be understood that the apparatus I have shown and explained is to be regarded as an illustrative and not an exclusive embodiment of my invention; for it is obvious that details may be modified, as by the use of mechanical equivalents and the like, without departing from the spirit of my invention and the scope of' the claims.

Having thus describedmy invention, what I claim and desire to secure by Letters Patent of the United States is a 1. In an under-feed stoker for broken coal of thecharacter described, the combination with a-coal hopper provided with an open top to admit coal, of a dust hood partially above the open top, a fire pot, a coal duct, a feed screw in the coal duct to carry the coal from the hopper to the fire pot, a blower, an air duct, independent or the coal duct, from the duct, from the blower to the fire pot, and a dust duct extending vfrom the hood to the blower intake.

blower, an air duct, independent of the coal 3. In an under-feed stoker for broken coal I of the character described, the combination with a coal hopper provided with an open top to admit coal, of adust hood partially above the open top and having an end projecting beyond the hopper, a downwardly and inwardly sloping interior flange around the uncovered edges of the open top, a fire pot,-

a coal duct, a feed screw in the coal duct to carry the coal from the hopper to the fire pot, a blower, an air duct, independent of the coal duct, from the blower to the fire pot,

and a dust duct extending from the projecting 7 end of the hood to the blower intake.

RALPH D. CRAWFORD. 

